Purpose :
Unintended suture rupture during knot construction is never a welcome event. Unrecognized differences in the performance of surgical devices may contribute to the rates of unexpected suture breaks. Unfortunately, many of the mechanical principals used in microsurgery are based on studies of large gauge sutures or are purely anecdotal.

Methods :
Five study groups, consisted of two suture types (Vicryl; Ethicon Inc) and (Polysorb; Covidien-Medtronic Inc), were tested by constant elongation for maximum load tolerance. The groups contained permutations of suture stress; stimulating knot construction, and included linear pull, knot pull, instrument compression, suture bend, and stretch to the point of plastic deformation. There was a total of 60 trials with over 13,180 observations.

Results :
During linear tests, Polysorb was 36%, p<0.001, stronger than Vicryl. Knot placement decreased load tolerance by 28% and 48%, p<0.001, for Polysorb and Vicryl respectively. Both sutures demonstrated an elongation capacity of 30% and 25% when a knot was incorporated. The effects of instrumentation, deformation due to folding, and excessive suture stretch are still being evaluated.

Conclusions :
Lactomer suture demonstrates a higher load tolerance than polyglactin 910 during the linear pull, and knot pull tension tests. One-fourth to one-half of load tolerance is lost with knot formation, this finding was independent of throw amount. Both suture polymers were able to stretch at least 25% of their original length.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.